Energy extracted from energy sources such as sunlight and wind is not usually suitable for use in residential or industrial settings since most electrical equipment requires both relatively stable voltage amplitude, e.g. 120 V or 230 V, and a relatively stable frequency, e.g. 50 Hz or 60 Hz. However, power derived from sunlight or wind energy sources can be shaped to a stable alternating current (AC) using capacitive elements for smoothing, and power inverters for conversion from direct current/voltage (DC), typically via a battery, to alternating (ac) current/voltage. Other energy sources, such as fuel cells, also require power inverters in order to become suitable for powering AC equipment. In other cases, such as in the case of electric motors, a variable-frequency current is desirable. Battery-powered audio amplifiers also require a conversion from DC to a variable-frequency current.
Two-level and three-level inverters are most commonly used for converting current from a DC source to an AC current. Both types come in a variety of topologies each possessing its own set of advantages and drawbacks. In some situations, a three-level inverter will be advantageous. However, this type of inverters require three voltage levels, which in itself leads to more complex circuitry than two-level inverters. Furthermore, three-level inverters inherently require a higher minimum number of circuit components than two-level inverters do.
Power/energy efficient multiple output DC-DC power converters are generally desirable to decrease operational costs and minimize carbon footprint and may for instance be used in power inverters and AC power generators.